And accessing means actually connecting to it...i.e. getting and IP address and becoming a node of the network. Accessing doesn't necessarily mean trying to connect to an actual computer within that network. It's the actual act of intruding on that network that is the crime. So don't think that because"I just use the Internet" that you're not engaged in an illegal act.

If you don't have the explicit permission of the owner of the network, you are breaking the law.